Where Would You Find a Trapdoor Spider?

Trapdoor spiders are to be found just under the surface of the earth. They belong to the class of spiders called mygalomorphae which includes the bird-eating spiders of the tropics. All these spiders tend to be rather large. They have four lungs instead of two, and their jaws work vertically instead of sideways.

The trapdoor spider has perfected the art of burrowing underground. Its jaws are provided with a special row of teeth with which to dig out its home. It lines its burrow with silk and makes a trap-door consisting of layers of silk and earth. The outside of this door is coated with moss or some other form of camouflage.

The spider waits behind its trap-door, darting out to seize its prey. Trapdoor spiders are widespread throughout the hottest regions of the world, with comparatively few in the temperate zones. Specimens of up to four and a half inches have been found. It is estimated that some may live up to 20 years.

The trapdoor is difficult to see when it is closed because the plant and soil materials effectively camouflage it. The trapdoor is hinged on one side with silk. The spiders, which are usually nocturnal, typically wait for prey while holding on to the underside of the door with the claws on their tarsi.

Prey is captured when insects, other arthropods, or small vertebrates disturb the ‘trip’ lines the spider lays out around its trapdoor, alerting the spider to a meal within reach. The spider detects the prey by vibrations and, when it comes close enough, leaps out of its burrow to make the capture.

Male trapdoor spiders can overcome the female’s aggressive reactions to their approach, but it is not known how. Females never travel far from their burrows, especially if they have an egg sac. During this time, the female will capture food and regurgitate it to feed her spiderlings.

Enemies of the trapdoor spider include certain pompilids (spider wasps), which seek out the burrows and manage to gain entrance. They sting the owner and lay their eggs (usually one per spider) on its body. When the egg hatches, the larva devours the spider alive.

Content for this question contributed by Karrie Murphy, resident of Wilbraham, Hampden County, Massachusetts, USA